The present invention relates to the field of surgical instruments, and in particular, relates to the technology and instrumentation used to achieve pneumoperitoneum during laparoscopy and laparoscopic surgery.
Surgeons have used laparoscopic surgery to perform a variety of procedures. By manipulating laparoscopes and video telescopes, surgeons gain a visualization of the abdominal cavity while minimizing tissue and muscle injury that normally accompanies conventional invasive procedures. Compared to conventional surgery, laparoscopy reduces patient trauma, decreases patient recovery time, and yields significant cost savings by reducing post-operative care.
The proper hardware and instrumentation are essential to the performance of safe laparoscopic procedures. To create a sufficient area for the introduction of a laparoscope and other instruments, the abdominal wall is first raised from the organs enclosed in the abdominal cavity. Separation is conventionally attained by pressurizing the abdominal cavity with a suitable gas. Typically, carbon dioxide is used. The presence of artificial gas in the peritoneal cavity to achieve exposure during laparoscopy is referred to as pneumoperitoneum.
Two conventional techniques are practiced to create pneumoperitoneum. One technique to provide access into the intra-abdominal cavity consists of inserting a Verres needle through the umbilicus. A Verres needle is inserted through the subumbilical area until the tip of the needle communicates with the anterior abdominal wall. When the needle is at an appropriate depth, gas is infused through a hollow section of the needle by an insufflator until the abdomen is expanded away from the organs enclosed by the abdominal cavity. Once pneumoperitoneum is achieved, typically at a pressure between twelve to fifteen millimeters of mercury, the Verres needle is withdrawn and a trocar is inserted through the umbilical wound. Laparoscopic instruments are then inserted through the cannula to provide a direct vision of the surgery.
A second technique may also be practiced to create pneumoperitoneum. The second procedure, sometimes referred to as the Hassan procedure, involves making a small incision in the umbilicus and inserting a trocar prior to insufflating the abdominal cavity. Gas is then infused through the trocar to create pneumoperitoneum. A laparoscope and endoscopic instruments are then inserted through the trocar allowing the surgeon to view, examine, and operate in the abdominal cavity.
As laparoscopic procedures often require the manipulation of several instruments including a light source and a video source, additional trocars are frequently necessary. Because the trocars are of fixed diameter, their gas infusion ports do not always permit the sufficient flow of gas to sustain the intra-abdominal pressure needed to maintain pneumoperitoneum. The infusion pressure of the insufflating gas is generally limited to forty-five millimeters of mercury. Conventional insufflators limit gas flow rates to a maximum of about twenty liters per minute. However, current laparoscopic procedures suction blood, other fluids, and smoke for brief periods requiring flow rates in excess of twenty liters per minute. Recently, thirty and forty liters per minute insufflating machines have been introduced to the laparoscopic market. These machines may require custom trocars with exceptionally large infusion ports to sustain high gas flow rates. When these trocars are not used, the machines are limited to maximum flow rates of about twenty liters per minute.
Intra-abdominal pressure may be monitored by an external sense line. One practice relies on inserting a pressure sensor directly into the intra-abdominal cavity through a gas delivery channel or by direct measurement unencumbered by gas flowing through the delivery channel. One potential disadvantage associated with using an external sense line is that it may be blocked or open because of a failed connection or an obstruction within the abdominal cavity.
A commonly used process to monitor pressure in the intra-abdominal cavity is to stop the infusion of insufflation gas into the peritoneal cavity, allow the pressure to stabilize, and then measure a static pressure. Algorithms and predictive techniques are employed to calculate the intra-abdominal pressure. The "flow and stop" process causes the gas delivered in a unit of time or duty cycle to be lower than the peak flow rate of the machine. The duty cycle limitation prevents these machines from immediately reacting to unforeseeable pressure losses and gas leakage that flow from the insertion of trocars into the intra-abdominal cavity.
In light of the strengths and weaknesses of the above equipment, there is a need for an insufflation system, apparatus, and method for performing safe laparoscopy. The system, apparatus, and method should be capable of assuring continuity from the intra-abdominal cavity and through the external sense line, facilitate static and continuous pressure measurements, provide a continuous infusion gas flow, and be capable of detecting blocked or inadvertently disconnected gas output lines. To this end, the system, apparatus, and method should be simple to operate and provide visual and audio warnings to its operator.